Many attempts have been made to protect container contents from the deleterious effects of both outside elements and from residual chemicals within the container material itself.
Schoettle, U.S. Pat. No. 1,773,064, discloses a cardboard container wherein the inner layer of cardboard is coated with an acid in order to protect the contents of the container from alkaline fumes emitted from the adhesive used in container construction and/or sealing.
Palmer etal., U.S. Pat. No. 1,564,707, and Flynn, U.S. Pat. No. 2,144,453, both relate to packages specifically designed for photographic film. In the former, the wrapping comprising the container is substantially free from sulphur, ammonia, and turpentine. In the latter, there is a black, opaque outer layer and an inner layer which is described only as "inert towards light-sensitive, photographic emulsions".
Hutter, U.S. Pat. No. 2,534,201 discloses a container having metal corrosion inhibiting characteristics. This is achieved through the use of an inner layer comprised of both an organic amide and an inorganic metal nitrate.
Fox et al., U.S. Pat. No. 2,555,031, discloses a container for storing phosphatic fertilizers for extended periods by coating the inner layer of the container with a lime material.
Hollinger, U.S. Pat. No. 4,489,120, discloses a boxboard comprising a first layer of paperboard consisting of non-buffered, substantially pure alpha-cellulose and an alkaline size, a second layer of a paperboard comprising alpha-cellulose, an alkaline buffer and an alkaline size and, intermediate said first and second layers, a layer of water-impermeable plastic. Hollinger states that the inner layer is non-buffered in order to avoid damage to the contents of containers made from the boxboard.
A study by Parks et al. entitled "Studies on the Degradation Products of Paper with and without Pollutants in a Closed Environment: I. Preliminary Results", issued in 1990 by the National Institute of Standards & Technology (NIST), states that for papers aged in the presence of SO.sub.2, "High performance liquid chromatography (HPLC) on aqueous extracts showed eight peaks from the newsprint aged with SO.sub.2 and six peaks in the absence of SO.sub.2. Of the eight components found in newsprint aged in SO.sub.2, six were tentatively identified as 2-ketoglutaric acid, malic acid, malonic acid, succinic acid, formic acid, and acetic acid. In the absence of SO.sub.2, four acids were tentatively identified (malonic, succinic, formic and acetic acids)." The study tentatively identified two acids in a rag paper as malonic and succinic acid. The components included: 2-ketoglutaric acid [HOOCCO(CH.sub.2).sub.2 COOH], malic acid, malonic acid [CH.sub.2 (COOH).sub.2 ], succinic acid [(CH.sub.2).sub.2 (COOH).sub.2 ], formic acid (HCOOH), and acetic acid (CH.sub.3 COOH).
The study shows the existence of problems related to SO.sub.2 and other pollutants in archival containers. Also, in Table 1 on page 16 of the NIST study, the data shows that newsprint aged in air has a folding endurance of 4.9 double folds at a 600 gm load, and only 1.9 folds when aged with SO.sub.2 in the air. Similarly, the rag paper aged in air survived 34 double folds at a 1000 gm load, while the rag paper aged in SO.sub.2 and air survived only 10.5 folds at this load.
The NIST paper also states that "Sulfur dioxide absorbed into paper from the atmosphere is a suspected precursor of in situ hydrolysis through the formation of sulfurous acid, sulfuric or possible analogues with anhydrocellulose units." It is known that oxides of nitrogen combine with moisture to form nitric acid, and that these pollutants and others attack other artifacts such as photographs. Sulfur compounds cause silver images, e.g. in photographs or microfilm and microfiche, to fade as the metallic silver is converted to silver sulfide. Acids attack all of the components of the photograph; they can bleach the silver image, causing evident fading, and they can attack the paper and gelatin support, which can become brittle. Peroxides in concentrations as low as one part in thirty million can cause image oxidation and fading.
Other by-products of deterioration found by other researchers include low molecular weight ketones, aldehydes and phenols. The NIST researchers also discuss problems associated with trapped by-products of deterioration, stating that "Degradation products with significant vapor pressure at room temperature are kept in by the sealing of the papers in a container. The diffusion of these degradation products can occur in a variety of ways. They may become air borne and attach themselves to another paper or to another site on the same paper encouraging degradation there."
In the area of archival preservation, i.e., the preservation of papers, photographs, textiles and artifacts of historical, aesthetic or sentimental significance, containers have historically been fabricated from papers developed for the long-term preservation of paper documents. However, it has been discovered that stored archival materials produce various by-products of deterioration which accelerate the deterioration process. Moreover, various harmful pollutants, such as sulfur dioxide, are readily able to pass through conventional archival boxboards, and their entry is not prevented by alkaline materials contained in such boxboards. Even though the archival paper may absorb such pollutants, it will later release them and permit them to react with the artifacts contained therein.
Further, it has been observed that the actual configuration of the container may also contribute to the deterioration process. Generally, if the container utilized for the long term storage of archival documents is only partially filled, the archival documents stored inside will have a tendency to slide down across the bottom of the container and assume a curved shape. Over a period of time, this results in permanent deformation of the documents in a curved condition which makes them subject to cracking when removed, thus accelerating the deterioration process. In the past, attempts to prevent this curved condition have included stuffing crumpled paper in the open space of the container to maintain the documents in a flat condition and prevent them from sliding down and curving.
Accordingly, it is an object of the present invention to provide a container made from paper which does not contain substances that will deteriorate and release compounds which will be harmful to archival materials stored therein. It is a further object of the present invention to provide a durable container which will substantially diminish problems associated with accelerated deterioration of archival materials produced by the deterioration by-products of such materials. An additional object of the present invention is to provide a container which will permit the long term storage of documents without slippage of the documents or the resulting deformation. Other objects of the present invention will become apparent from the following description and the practice of the invention.